Summary

• keep the imported Android Java/project sources under platforms/android, while sharing Android C++ through NativeScript/runtime/android, NativeScript/napi/android, and NativeScript/ffi/jni/napi
• keep Apple FFI under NativeScript/ffi/objc and update generated-output/test wiring for the unified layout
• collapse Android HERMES and SHERMES onto the same Static Hermes (shermes) header/library surface already used by Apple; SHERMES remains only a compatibility engine selector
• harden JNI Node-API constructor/object fallback behavior for Static Hermes and preserve ObjC bridge ownership/expandos across Apple engines
• keep iOS/macOS direct engines unchanged in scope; Android-only engines were probed on Apple and remain unwired/unsupported for this PR

Commit Review Order

1. Layout moves and Android build wiring:
   • b16346f1 refactor: move objc ffi under platform namespace
   • 055964e5 refactor: move android jni napi ffi into shared tree
   • a0a2ed87 refactor: move android runtime sources into shared tree
   • 8d214e29 refactor: move android napi engines into shared tree
   • 04c486be refactor: wire android build to unified runtime layout
2. Behavior preservation and cleanup after the move:
   • 3aab3c3b fix(apple): update objc ffi generated paths
   • 4def1b90 fix(android): align hermes napi adapters
   • 86dec82f fix(android): preserve unified runtime behavior
   • da00c3af fix(android): stabilize runtime test harness
   • fd62fdb5 test(android): gate engine-specific runtime specs
   • 6bff08ee fix: clean up runtime refactor paths
3. Static Hermes unification:
   • 15d7c2a4 refactor(android): unify static hermes backend
4. Final review/test fixes:
   • 98918758 fix(jni): handle static hermes constructor receivers
   • 5bc35047 fix(objc): preserve bridge object ownership
   • 1668c885 fix(quickjs): clear weak refs before forced gc
   • 6ba820c1 test(ios): skip app main in scripted runner

Validation

• Android all-engine matrix, Pixel_9_Pro_API_36 emulator, JDK 17, logs in /tmp/ns-runtime-android-matrix-final3:
  • V8-10, V8-11, V8-13, QUICKJS, QUICKJS_NG, HERMES, SHERMES, JSC, PRIMJS: all PASS
• iOS simulator direct-engine matrix, logs in /tmp/ns-runtime-apple-matrix-final7:
  • v8: 713 specs, 0 failures, 13 skipped
  • hermes: 713 specs, 0 failures, 11 skipped
  • quickjs: 713 specs, 0 failures, 13 skipped
  • jsc: 713 specs, 0 failures, 13 skipped
• macOS direct-engine matrix, logs in /tmp/ns-runtime-apple-matrix-final7:
  • v8: 713 specs, 0 failures, 10 skipped
  • hermes: 713 specs, 0 failures, 8 skipped
  • quickjs: 713 specs, 0 failures, 10 skipped
  • jsc: 713 specs, 0 failures, 10 skipped
• Android-only engine probe on Apple CMake: primjs, quickjs_ng, v8-10, v8-11, and v8-13 are still unsupported/unwired on Apple in this PR
• Hygiene:
  • git diff --check
  • npm run check:ffi-boundaries
  • python3 -m py_compile metadata-generator/build-step-metadata-generator.py
  • stale-path/debug sweeps for removed Hermes/fbjni paths and temporary ObjC debug prints